It is well-known that scattered radiation impairs the image quality, particularly in the case of imaging tomography equipment such as, for example, X-ray computed tomography devices. It is for this reason that such tomography devices generally comprise radiation detectors which have so-called scattered radiation collimators arranged upstream of them in order to reduce the scattered radiation.
Known scattered radiation collimators comprise, for example, absorber elements which are arranged next to one another in a collimation direction and are aligned in one direction with respect to their longitudinal extent, with absorber surfaces of the absorber elements running substantially perpendicular to the respective collimation direction. This makes it possible to suppress scattered radiation occurring in the collimation direction, which scattered radiation is caused, for example, by the radiation being scattered on an object to be examined.
For example, DE 103 61 510 A1 discloses a collimator for a computed tomography scanner, which has a collimator lower part and a collimator upper part as holders for collimator plates. The collimator lower part comprises groove-like recesses on the end face for collimator plates in addition to lug receptacles on the bottom side. The collimator upper part is screwed to the collimator lower part in order to form the collimator.
US 2006/0233298 A1 describes a collimator with an upper and a lower annular-segment-like holding element. The holding elements have grooves for collimator sheets. The annular-segment-like holding elements are connected to each other by means of side parts.
The absorber elements of known scattered radiation collimators are generally comparatively thin and delicate. As a result of this, the absorber elements as such have low mechanical stability and are therefore not very dimensionally stable. Particularly in the case of acting forces, such as, for example, centrifugal forces acting on the absorber elements and transverse forces acting across the connection axis X-ray tube/X-ray detector during the operation of an X-ray computed tomography device, and other mechanical effects, the absorber elements can be deformed to such an extent that artifacts occur as a result of this. By way of example, this can be the case if the—or individual—absorber elements are deformed or displaced to the extent that detector elements of the radiation detector are shadowed.
In order to avoid deformations and temporary displacements or erroneous positioning, it is common practice, for example, to adhesively bond the absorber elements using suitably designed holding lugs which extend into the intermediate spaces between the absorber elements. Aside from the comparatively high production complexity, this additionally poses the problem of irreversible erroneous positioning of the absorber elements possibly being caused by adhesive bond contraction during the curing of an adhesive bond used for the adhesive bonding.
DE 10 2005 028 411 A1 describes a collimator for a beam detector which has a number of collimator sheets arranged next to one another and between which respectively at least one support element is arranged for stiffening the collimator, which support element is composed of an X-ray transparent material and supports the collimator sheets from the side.